Optical article comprising an antireflective coating with a very low reflection in the visible region

Abstract

This invention relates to an ophthalmic lens comprising a transparent substrate with a front main face and with a rear main face, at least one of the main faces being coated with a multilayered antireflective coating comprising a stack of at least one layer having a refractive index higher than or equal 1.5 and at least one layer having a refractive index lower than 1.5, such that:—the mean light reflection factor in the visible region R v is lower than or equal to 0.5% for an angle of incidence lower than 35°;—the Chroma C* is equal or higher than 18, preferably 20, according to the international colorimetric CIE L*a*b* for an angle of incidence (Θ) of 15°.

The invention claimed is: 
     
       1. An ophthalmic lens comprising a transparent substrate with a front main face and with a rear main face, at least one of the main faces being coated with a multilayered antireflective coating comprising a stack of at least one layer having a refractive index higher than or equal 1.5 and at least one layer having a refractive index lower than 1.5, such that:
 the mean light reflection factor in the visible region R v  is lower than or equal to 0.5%, for at least an angle of incidence lower than 35°; 
 the Chroma C* is equal or higher than 18 for an angle of incidence (θ) of 15°. 
 
     
     
       2. The ophthalmic lens according to  claim 1 , wherein the multilayered antireflective coating has a hue (h) from 275° to 325° at an angle of incidence (θ) of less than or equal to 30°. 
     
     
       3. The ophthalmic lens according to  claim 1  or  2 , wherein the multilayered antireflective coating has a Chroma C*, which is lower than or equal to 11 for an angle of incidence (θ) higher than 35°. 
     
     
       4. The ophthalmic lens according to  claim 1  or  2 , wherein the multilayered antireflective coating has a mean reflection factor R UV  between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, lower than 13% for an angle of incidence in the range from 20° to 50°. 
     
     
       5. The ophthalmic lens according to  claim 4 , wherein the multilayered antireflective coating has a mean reflection factor R UV  between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, lower than 13% for an angle of incidence in the range from 30° to 45°. 
     
     
       6. The ophthalmic lens according to  claim 1  or  2 , wherein the multilayered antireflective coating has a mean reflection factor in the visible region R m  lower than or equal to 1.15% for an angle of incidence lower than or equal to 35°. 
     
     
       7. The ophthalmic lens according to  claim 6 , wherein the multilayered antireflective coating has a mean reflection factor in the visible region R m  lower than or equal to 1.15% for an angle of incidence lower than or equal to 15°. 
     
     
       8. The ophthalmic lens according to  claim 1  or  2 , wherein the multilayered antireflective coating comprises a number of layers higher than or equal to 3. 
     
     
       9. The ophthalmic lens according to  claim 8 , wherein the multilayered antireflective coating comprises a number of layers higher than or equal to 4. 
     
     
       10. The ophthalmic lens according to  claim 1  or  2 , wherein the multilayered antireflective coating comprises a number of layers lower than or equal to 7. 
     
     
       11. The ophthalmic lens according to  claim 10 , wherein the multilayered antireflective coating comprises a number of layers lower than or equal to 6. 
     
     
       12. The ophthalmic lens according to  claim 10 , wherein the multilayered antireflective coating comprises a number of layers lower than or equal to 5. 
     
     
       13. The ophthalmic lens according to  claim 9 , wherein the antireflective coating comprises at least two layers having a refractive index equal to or higher than 1.5 and at least two layers having a refractive index lower than 1.5. 
     
     
       14. The ophthalmic lens according to  claim 1  or  2 , wherein the antireflective coating is deposited on a silica-based sub-layer layer having a thickness of from 100 to 300 nm. 
     
     
       15. The ophthalmic lens according to  claim 1  or  2 , wherein the antireflective coating outer layer is a silica-based layer. 
     
     
       16. The ophthalmic lens according to  claim 13 , wherein the antireflective coating comprises, in the direction moving away from the substrate, a layer having a refractive index higher than or equal to 1.5 with a thickness of from 10 to 25 nm, a layer having a refractive index lower than 1.5 with a thickness of from 20 to 35 nm, a layer having a refractive index higher than 1.6 with a thickness of from 60 to 105 nm, optionally an electrically conductive layer with a thickness of from 3 to 10 nm, and a layer having a refractive index lower than 1.5, with a thickness of from 70 to 105 nm. 
     
     
       17. The ophthalmic lens according to  claim 16 , wherein the antireflective coating comprises, in the direction moving away from the substrate, a layer having a refractive index higher than or equal to 1.5 with a thickness of from 14 to 22 nm, a layer having a refractive index lower than 1.5 with a thickness of from 27 to 32 nm, a layer having a refractive index higher than 1.6 with a thickness of from 68 to 90 nm, optionally an electrically conductive layer with a thickness of from 4 to 8 nm, and a layer having a refractive index lower than 1.5, with a thickness of from 87 to 95 nm. 
     
     
       18. The ophthalmic lens according to  claim 1  or  2 , wherein the rear main face and the front main face of the ophthalmic lens are coated with said multilayered antireflective coating. 
     
     
       19. The ophthalmic lens according to  claim 18 , wherein the front face comprises a multilayered antireflective coating having a hue (h) from 275° to 325° at an angle of incidence (θ) of less than or equal to 30°. 
     
     
       20. The ophthalmic lens according to  claim 19 , wherein the rear face comprises a multilayered antireflective coating having a mean reflection factor R UV  between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, lower than 13% for an angle of incidence in the range from 20° to 50°. 
     
     
       21. The ophthalmic lens according to  claim 19 , wherein the rear face comprises a multilayered antireflective coating having a mean reflection factor R UV  between 280 nm and 380 nm, weighted by the function W(λ) defined in the ISO 13666:1998 standard, lower than 13% for an angle of incidence in the range from 30° to 45°.